This invention relates to a unique latch construction and more particularly, to one which may be provided in a relatively wide variety of choices of different constructions, yet each may include certain features with each comprising patentable ingenuity. The latch construction may be of relatively simple form having a single latchbolt with an interior operator and an exterior operator, the latter comprising a unique form of rack and pinion. This rack and pinion as an exterior operator may also have added thereto a lock for shifting the rack and pinion to also place it in either of its operable or non-operable positions. Still an addition and of more complexity, a second latch construction may be added to the first latch construction with it having merely a single exterior operator or a single interior operator or both. The two latch constructions may be operably connected by a motion transferring yoke which merely just unlocks the first latch construction by means of unlocking the second latch construction, or the latchbolts may be connected by a panic assembly which withdraws the second latchbolt when the first inside operator is actuated to withdraw the first latchbolt, or both of these motion transferring yoke and panic assemblies may be added. Thus, it is seen that a wide variety of beneficial features may be added to the construction, all according to the principles of the present invention.
Various forms of rack and pinion constructions have been used for providing the withdrawal motion in latchbolt structures. In most cases, the purpose of the rack and pinion arrangements is merely to withdraw the bolt once the bolt has been freed of any locking mechanism, in other words, the bolt is locked independently of any movement action by the rack and pinion arrangement. There have been some of the rack and pinion constructions which have included locking means directly therein but, to our knowledge, these have been locking arrangements which directly block the rack and pinion movement as opposed to blocking the bolt movement.
In the lockable rack and pinion constructions, there has never been also connected thereto the various of the different other latchbolt features and the structure required for such connections. For instance, there have never been, to our knowledge, a single latchbolt construction having an exterior lock and an interior operator, both of which control the shifting of the rack and pinion between engaged and disengaged positions. There has never been, to our knowledge, a double latchbolt construction which has cooperable elements therein providing the shifting of the first latchbolt rack and pinion between its engaged and disengaged positions by elements in the second latchbolt construction. There has never been, to our knowledge, a double latchbolt construction having a panic assembly therein which bypasses the rack and pinion construction provided for the first latchbolt and actuates both of the latchbolts simultaneously from the interior side to swiftly release the particular door being retained.